Thorium Reader review
A free, accessible reader for EPUB, PDF, DAISY, and Web Publications.
Reviewed by iTechGuides Editors · Editorial team · Updated Oct 2026
Thorium Reader is a free digital reading application and personal library for ebooks, audiobooks, comics, manga, and documents. It is suited to readers who need broad accessibility support, offline access, and compatibility with EPUB, PDF, DAISY, and Web Publications. The application runs on Windows, macOS, Linux, iOS, and iPadOS, making it relevant for desktop and mobile reading across common personal devices. EDRLab develops and maintains the application as a nonprofit focused on open standards, literacy, and accessibility.
Thorium Reader’s pricing is straightforward: the application is free across its supported platforms, with no paid tiers described. The free product includes library organization, customizable text size, themes, spacing, fonts, and reading modes. Readers can add, edit, tag, export, and import bookmarks, create annotations with comments and tags, search within ebooks, and navigate search results. Downloaded publications can be read offline, which suits users who want local access without requiring a continuous connection. Its documented format coverage is broad for reading-focused software, including EPUB 2 and 3, Fixed Layout EPUB, PDF, DAISY 2.02 and 3, and Web Publications.
The ecosystem fit is a key strength. Users can browse and download content from OPDS catalogs, access Project Gutenberg and LibriVox content, and open Readium LCP-protected publications. Accessibility features include keyboard navigation and screen-reader support, while reading settings can be adjusted for different preferences. Choose Thorium Reader if accessible reading, open standards, DRM support, annotations, and offline access matter more than a paid service layer. Readers who need downloaded content organized across a wider set of formats or who depend on an ecosystem outside its documented standards should consider whether its supported formats and catalog connections fit their library.
Thorium Reader pros and cons
- Where it wins
- Supports EPUB, PDF, DAISY, and Web Publications
- Includes annotations, bookmarks, search, and offline reading
- Offers keyboard navigation and screen-reader support
- Where it doesn't
- Offline reading applies to downloaded publications
- OPDS browsing depends on available catalogs
- Readium LCP support is limited to protected LCP publications
Thorium Reader fact sheet, pricing and score →
Advertiser disclosure: iTechGuides is reader-supported. Vendors can pay for top positions in our rankings and for a place on other products' pages, and we may earn a commission when you click some links. Bought places stand at the number bought; this page and our disclosure say so. Paying vendors may get a fuller, more detailed review from our editors, and that review can change their score. How we rank.
Last updated · How we research and update